1. Field of the Invention
The present invention relates to a wrapping machine for use in a packaging system, wherein a flat sheet for wrapping an article, is folded to form a U-shaped case and inner flaps of the case are folded and glued and then, side flaps of which are folded and pressed to the inner flaps while the case is transported.
2. Description of the Related Art
A conventional wrapping machine includes a bucket conveyor on which a flat sheet is placed. Arranged on the sheet is an article to be wrapped. Front and rear flaps of the sheet are folded toward the front and rear sides of the article by flap folding guides to thereby form a U-shaped case. This case, with the article placed thereon, is advanced by the bucket conveyor. Inner flaps of the U-shaped case are folded toward the right and left sides of the article by an inner flap folding mechanism, said folding mechanism including flap guides and swing cutters. Arranged on both sides of the bucket conveyor are a side flap folding mechanism including fixed guide bars and guide plates, and a gluing mechanism including four hot-melt applicators. Side flaps of the U-shaped case are folded 45.degree. relative to both sides of the article, and maintained in its state by means of the guide plates. Glue is then applied to predetermined outer surfaces of the inner flaps by the four hot-melt applicators. Thereafter, the side flaps are folded up to 90.degree. by the fixed guide bars. The side flaps are pressed, by a press mechanism, onto the inner flaps to form a case. This case is intended to cover the lower half of the article wrapped therein.
It should be mentioned that when the machine is in its inoperative state, hydraulic cylinders are actuated to raise the guide plates from 45.degree. to 90.degree. so as to press the side flaps onto the inner flaps for joining purposes.
In such a conventional wrapping machine, however, folding operation of the fixed guide bars is not adequately carried out. As a consequence, cases, when completed, may not uniformly be shaped. Moreover, a space is necessary to arrange the fixed guide bars. This arrangement will require longer size of the machine.